Rockwell-automation 1771-IFF/A INSTL.INSTR FAST ANALOG INPUT Instrukcja Użytkownika Pobierz pdf (Strona 10)

Publication 1771-IN046B-EN-P - December 2003

10 Fast Analog Input Module

Input connections for the 1771-IFF with:

• single-ended inputs are shown on page 11.

• differential inputs are shown on page 12.

Minimizing Ground Loops

To minimize ground loop current on input circuits:

• use single-ended mode whenever possible

• use 2-wire transmitters with a common power supply

• separate 2-wire and 4-wire transmitters between different modules

• tie 4-wire transmitter and/or separate power supply grounds together

Cable Lengths

Recommended maximum cable length for voltage-mode input devices is 50

feet (15.24m), due to possible signal degradation and electrical noise immunity

in typical industrial environments. Cable length for current-mode input devices

need not be as restrictive because analog signals from these devices are less

sensistive to electrical noise interference.

WARNING

If you connect or disconnect the wiring with field-side

power applied, an electrical arc can occur. This could cause

an explosion in hazardous location installations.

Be sure that power is removed or the area is nonhazardous

before proceeding.

IMPORTANT

Mixing 2-wire and 4-wire transmitter inputs on the same

module is not recommended. Power supply placement can

make it impossible to eliminate ground loops.

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Rockwell-automation 1771-IFF/A INSTL.INSTR FAST ANALOG INPUT Instrukcja Użytkownika Strona 10